JPH06146258A - Method of reinforcing existing base - Google Patents

Abstract

PURPOSE:To enhance the workability for increasing the bearing force of an existing base. CONSTITUTION:A shaft 2 is drilled in the foundation around or through an existing base 1, and a guide pipe 3 is inserted into the shaft 2. Ultrahigh pressure jet water containing hardener is injected into the underground through the guide pipe 3 so as to mix the hardener and sediment together obtained by cutting the foundation around the guide pipe 3. Then, thus obtained mixture is then directly hardened so as to form a foot protection part 4 underneath the bottom surface of the existing base 1, the foot protection part 4 having a planar area which is larger than that of the existing base 1. With this arrangement, a necessary bearing force may be ensured so as to eliminate the necessity of troublesome work for building a new base, thereby it is possible to enhance the workability and to shorten the construction period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing an existing foundation which enhances the bearing capacity of the existing foundation.

[0002]

2. Description of the Related Art The foundation of an existing building has a reduced supporting strength due to a change in ground bearing capacity or the weight of a building increases due to an increase in the building foundation. Reinforcement is needed to increase the bearing capacity of the.

Conventionally, a new foundation is constructed beside an existing foundation to increase the bearing capacity by enlarging the bottom area of the entire foundation, but the newly constructed foundation is located around the existing foundation. Since it is limited, the construction area will be expanded, and since it is necessary to secure the integrity of the new foundation and the existing foundation, the construction will be performed after cutting the ground around the existing foundation once,
Generally, the workability is poor and the construction period tends to be long because multiple steps and complicated work are required, such as removing the concrete surface layer, connecting the existing reinforcing bar and the new reinforcing bar, and placing concrete.

The present invention has been made in view of the actual situation of a conventional reinforcing method for an existing foundation, and intends to newly propose a reinforcing method having high workability.

[0005]

According to the present invention, a jet jet is used to cut the ground while jetting the hardening material into the ground below and around the bottom of the existing foundation, and at the same time, the cut earth and sand and the hardening material are removed. By mixing and improving the surrounding ground of the existing foundation, a consolidation section with a flat area larger than that of the existing foundation is created, and the conventional construction method is achieved by securing the necessary bearing strength at this consolidation section. It eliminates the complexity of and improves the workability.

[0006] For the construction, from the side of the existing foundation or through the existing foundation, a vertical hole is bored in the ground, a guide pipe is inserted into the vertical hole, and an ultra-high pressure jet jet containing a hardening material is introduced through the guide pipe. It is injected into the ground and mixed with hardened material and cutting soil while cutting the ground around the guide pipe, and by hardening the mixture as it is, it is larger under the bottom of the existing foundation or its surroundings. A pillar-shaped root consolidation part with a flat area is created.

[0007] The root consolidation portion is formed below or around the bottom surface of the existing foundation to support the existing foundation, and has a flat area larger than that of the existing foundation to compensate for the proof stress that the existing foundation lacks and to load the building. Secure a support capacity according to.

There is no need to expand the construction area on the ground by constructing the ground on the bottom surface of the existing foundation through the guide pipe to the target ground, and integrating with the existing foundation. By eliminating the need for complicated work, the workability and efficiency are improved, and the construction period is shortened. In addition, it is possible to implement it regardless of the form of the existing foundation by obtaining the necessary bearing strength by constructing the root consolidation part without modifying the existing foundation.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment.

In the present invention, as shown in FIGS. 1 and 2, the guide pipe 3 is inserted from the side of the existing foundation 1 or into the vertical hole 2 penetrating the existing foundation 1 and drilled in the ground. To cut the ground by jetting an ultra-high pressure jet jet containing hardening material into the ground near the bottom surface of the existing foundation 1 and at the same time mixing the hardening material and cutting earth and sand, and hardening this mixture to the bottom surface of the existing foundation 1. This is a method in which a root consolidation portion 4 having a larger plane area is formed in the vicinity thereof and the bearing strength of the existing foundation 1 is supplemented by the root consolidation portion 4.

FIG. 1 shows an embodiment in which the existing foundation 1 is a direct foundation, and the root consolidation portion 4 is constructed below the bottom surface of the existing foundation 1. As shown in Fig. 2, it is constructed into a column with a large diameter, such as a column, by supporting it around the bottom of the base or around the existing foundation 1 including the bottom of the bottom, as shown in Fig. 2. To be done.
The vertical hole 2 is bored to the construction depth of the root consolidation portion 4, and the guide pipe 3 is inserted into the vertical hole 2 by the construction machine 5.
As shown in FIG. 2, the guide pipes 3 are arranged on a plane at an interval such that adjacent root consolidation portions 4 and 4 overlap each other.

After the guide pipe 3 is inserted, an injection nozzle (not shown) attached to the construction machine 5 is inserted to the tip of the guide pipe 3, and an ultra-high pressure jet jet containing a hardening material is jetted from the injection nozzle toward the ground. , The ground around the guide pipe 3 is cut by a jet jet, and the hardened material and cutting soil are mixed to improve the ground near the bottom of the existing foundation 1, and the mixture is hardened as it is to build the root consolidation part 4. To do. Rooting part 4 is for each guide pipe 3,
It is constructed by wrapping each other, and by gathering a plurality as shown in FIG. 2, the area is wider than the plane area of the existing foundation 1.

FIG. 3 shows a case where the existing foundation 1 is a pile foundation, and the pile 6 is
2 shows an embodiment in the case where a root-hardening portion 4 is constructed around the tip of the root fixing portion 4 in such a manner as to cover the tip portion. In this case, the vertical hole 2 is drilled from the periphery of the existing foundation 1 to the tip of the pile 6, and by performing the same construction as in the case of FIG. 1, as shown in FIG. Rooting part 4 is created.

FIG. 5 shows a case in which a vertical hole 2 is bored through the existing foundation 1 of the pile foundation, and a rooting portion 4 is formed around the bottom of the bottom of the tip of the pile 6. In any case, root fixing part 4
Supports the load of the building together with the existing foundation 1 by supporting the existing foundation 1.

[0015]

As described above, the present invention is as described above, in which the hardened material is injected into the ground while cutting the ground around the existing foundation by using the jet jet, and at the same time, the cut earth and sand and the hardened material are mixed, By improving the ground around the existing foundation, a root consolidation section with a flat area larger than that of the existing foundation is created, and this bearing consolidation section secures the necessary bearing capacity.
Since the construction area on the ground is not enlarged and the complicated work for integrating with the existing foundation is not required, the workability and the construction efficiency are improved, and the construction period can be shortened.

In addition, since the formation of the root consolidation portion is performed by ground improvement, it is possible to perform construction on various existing foundations regardless of the form of the existing foundation.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment in which an existing foundation is a direct foundation.

FIG. 2 is a plan view of FIG.

FIG. 3 is a vertical sectional view showing an example in which the existing foundation is a pile foundation.

FIG. 4 is a plan view of FIG.

FIG. 5 is a vertical cross-sectional view showing an embodiment in which a vertical hole is bored through an existing foundation.

[Explanation of symbols]

1 ... Existing foundation, 2 ... Vertical hole, 3 ... Guide pipe, 4
…… Rooting part, 5 …… Construction machine, 6 …… Pile.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Fujimura 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Within Kashima Construction Co., Ltd. (72) Hiroaki Kubo 1-6-4 Moto-Akasaka, Minato-ku, Tokyo No. Chemikarugrout Co., Ltd. (72) Inventor Minoru Yamamoto No. 6-4 Moto-Akasaka, Minato-ku, Tokyo Chemikarugrout Co., Ltd.

Claims (1)

[Claims] 1. An ultrahigh-pressure jet jet containing a hardening material is formed from the side of an existing foundation or through the existing foundation by forming a vertical hole in the ground, inserting a guide pipe into the vertical hole. Spraying into the ground, mixing hardener and cutting soil while cutting the ground around the lower end of the guide pipe, and hardening this mixture as it is, under the bottom of the existing foundation or in the vicinity, a larger flat area than the existing foundation. Reinforcement method for existing foundation to create pillar-shaped root consolidation part.